The custom-made ceramic from South Korea used in the diffuser has microscopic holes, resulting in a very fine and thorough air bubble diffusion. It ensures a high level of CO2 saturation in your aquarium. The fine Co2 mist easily breaks down in the water column and is absorbed by the aquatic plants.The elegant and sturdy ceramic disc is microporous and is permanently glued to an acrylic bubble counter to hold under high pressure and create a superfine Co2 mist. The ceramic disc is made of high quality transparent acrylic and is not easy to break during the maintenance of the aquarium.The included Co2 diffuser with suction cup allows the user to safely place in the corner of the planted aquarium.Only 20 PSI (1.37 bar) required, the CO2 diffuser works with all CO2 systems, including DIY levels. Recommended pressure higher than 25 PSI.3 models for different pool sizes. S for 1-2 bps (bubbles per second), for 13 gal or less. M for 2-3 bps (bubbles per second), for 13-32 gal. L for >3 bps (bubbles per second), for 32 gallons or more